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Dissertation
Manure application effects on nitrogen pools in a subtropical soil of Oman
(2019-04)
Agricultural productivity of the millennia-old oasis agriculture in Oman is based on the continuous application of high rates of goat and sheep manure combined with flood irrigation. The high nitrogen (N) and carbon (C) turnover in these systems is a result of year-around high temperatures and continuous soil moisture, but knowledge is lacking on how N and C are transformed under these conditions. Therefore, this study aimed at investigating the N movement in different soil N pools. To this end a field experiment was ...
Dissertation
Assessment and use of sea buckthorn and apple diversity in northern Pakistan
(2020-12-03)
Many local perennial plant genetic resources (P/PGR) are under threat due to over-exploitation, depletion, degradation, farmers’ favoring few cash crops, poor marketing conditions leading to low product prices along with the lack of knowledge about alternative uses and management strategies. Such processes often cause the underutilization and replacement of local P/PGR causing them to become neglected and underutilized species (NUS). The decline of species abundance may cause genetic erosion of these NUS crops and ...
Aufsatz
Morphological and Genetic Diversity of Sea Buckthorn (Hippophae rhamnoides L.) in the Karakoram Mountains of Northern Pakistan
(2018-07-30)
Sea buckthorn (Hippophae rhamnoides L.) is a dioecious, wind-pollinated shrub growing in Eurasia including the Karakoram Mountains of Pakistan (Gilgit-Baltistan territory). Contrary to the situation in other countries, in Pakistan this species is heavily underutilized. Moreover, a striking diversity of berry colors and shapes in Pakistan raises the question: which varieties might be more suitable for different national and international markets? Therefore, both morphological and genetic diversity of sea buckthorn ...
Aufsatz
Estimation of Vegetable Crop Parameter by Multi-temporal UAV-Borne Images
(2018-05-22)
3D point cloud analysis of imagery collected by unmanned aerial vehicles (UAV) has been shown to be a valuable tool for estimation of crop phenotypic traits, such as plant height, in several species. Spatial information about these phenotypic traits can be used to derive information about other important crop characteristics, like fresh biomass yield, which could not be derived directly from the point clouds. Previous approaches have often only considered single date measurements using a single point cloud derived ...
Dissertation
Challenges to ecosystem services of sustainable agriculture in West Africa
(2020)
Food security is still sub-optimal in many parts of West Africa calling for more efficient agricultural practices in mitigating food insecurity. Some of the problems faced in West African agricultural systems are bottlenecks in ruminant livestock supply, inefficiency in commercial poultry production, and loss of arthropod diversity. These issues require proper integration of farming systems, demand the closing of nutrient cycles, need diversi cation of production, and require enhancement of ecosystem services. To ...
Dissertation
Integrated soil fertility management in eastern and western Africa: The role of knowledge and innovation systems, its adoption and impact
(2017-01-31)
The rise in population growth, as well as nutrient mining, has contributed to low agricultural productivity in Sub-Saharan Africa (SSA). A plethora of technologies to boost agricultural production have been developed but the dissemination of these agricultural innovations and subsequent uptake by smallholder farmers has remained a challenge. Scientists and philanthropists have adopted the Integrated Soil Fertility Management (ISFM) paradigm as a means to promote sustainable intensification of African farming systems. ...
Dissertation
Nitrogen use efficiency and optimization of nitrogen fertilizer application for stable yields and high quality of cereals grown in conservation agriculture
(2017-01-23)
In most agroecosystems, nitrogen (N) is the most important nutrient limiting plant growth. One management strategy that affects N cycling and N use efficiency (NUE) is conservation agriculture (CA), an agricultural system based on a combination of minimum tillage, crop residue retention and crop rotation. Available results on the optimization of NUE in CA are inconsistent and studies that cover all three components of CA are scarce. Presently, CA is promoted in the Yaqui Valley in Northern Mexico, the country´s major ...
Dissertation
Water use efficiency and management of agro-pastoral landuse systems in the Mongolian-Chinese Altay
(2017-02-08)
The use of organic fertilizers is an important approach to maintain soil fertility of irrigated agricultural land under the semi-arid climate conditions of Oman. However, gaseous emissions of carbon and nutrients from soil and organic fertilizers are a major challenge. Activated charcoal and tannins have the potential to reduce gaseous losses of carbon and nitrogen. Therefore, gaseous emissions of carbon dioxide (CO2), ammonia (NH3) and nitrous oxide (N2O) were measured by a photo-acoustic infrared multi-gas monitor. ...
Dissertation
Effects of activated charcoal and quebracho tannins on the turnover of goat manure in irrigated organic agriculture of the subtropics
(2015-04-15)
Agriculture in semi-arid and arid regions is constantly gaining importance for the security of the nutrition of humankind because of the rapid population growth. At the same time, especially these regions are more and more endangered by soil degradation, limited resources and extreme climatic conditions. One way to retain soil fertility under these conditions in the long run is to increase the soil organic matter. Thus, a two-year field experiment was conducted to test the efficiency of activated charcoal and quebracho ...
Dissertation
Effects of phosphorus and water stress on shoot and root growth and on mycorrhization of different pearl millet (Pennisetum glaucum (L.) R. Br.) varieties from West Africa
(2015-03-13)
This research work aimed at investigating the physiological mechanisms of tolerance of pearl millet to low soil Phosphorus availability and drought under the Sahelian conditions.